Comparative H diffusion measurements were performed on Armco Fe in 0.1M NaOH solution. The results revealed a marked superiority of alternating-current techniques over direct-current ones. The lattice diffusion of H could be determined on the basis of the phase difference between the input and the output currents for 1mm membranes at frequencies ranging from 10 to 40mHz. The H diffusivity which was measured at room temperature was equal to 6.2 x 10-5cm2/s for annealed Armco-Fe.

F.Veniali, Z.Szklarska-Smialowska: Materials Chemistry and Physics, 1986, 15[6], 545-57

Table 59

Diffusivity of H in Fe at 25C